Really? you think people would re-watch teletubbies for nostalgia purposes?
Think of it this way. The people who developed the show had to ensure that it was suitable for kids. Which means that they watched it. I'm guessing to some extent they also enjoy seeing their work. I can't imagine someone sitting down and marathoning it though. But again, different age ranges. Teletubbies is a much younger audience. While the ponies are around "10 year old' range. And yes, I can certainly see people enjoying that age range of cartoons. Considering stuff like marvel cartoons and the like are aimed at that age as well.
Same medium and age range, different theme.